Sea urchin histone genes will be mapped with restriction endonucleases, purified histone mRNAs, homologous RNA polymerases and DNA sequencing techniques in order to elucidate the mechanisms of regulation of these specific protein coding genes. BIBLIOGRAPHIC REFERENCES: Kedes, L.H., Cohn, R.H., Lowry, J.C., Chang, A.C.Y. and Cohen, S.N.: The organization of sea urchin histone genes. Cell. 6:359-369, 1975. Lifton, R.P. and Kedes, L.H.: Size and sequence homology of masked maternal and embryonic histone messenger RNAs. Develop. Biol. 48: 47-55, 1976.